Supporters of the ousted president, Kurmanbek Bakiyev, seized control of government buildings in three southern regions of the impoverished Central Asian state.
In an apparent coup attempt, Mr Bakiyev's followers stormed civic buildings in the cities of Osh, Jalalabad and Batken, kidnapped the governor of Jalalabad region and tried to take control of the area's main airport in Osh.
"The interim government views today's events in Osh... as an attempt by former president Bakiyev's associates to regain power," a government spokesman told Russia's Interfax news agency.
There were no reports of deaths but the unrest was the biggest challenge to the interim government, formed last month after a popular revolt toppled Mr Bakiyev from power and forced him to flee to the former Soviet republic of Belarus.
Any worsening of tensions in the south, at the heart of the region's most flammable and ethnically divided corner, would be of concern to world powers keen to maintain stability in Central Asia, a vast Muslim region north of Afghanistan.
Belarus, whose maverick leader Alexander Lukashenko refused to extradite Mr Bakiyev to face charges in Kyrgyzstan, said yesterday that all its diplomats had left the Kyrgyz capital, Bishkek, "for security reasons".
Russia and the US, which both have military bases in Kyrgyzstan, backed the interim government that came to power following the overthrow of Mr Bakiyev.Reuse content